Electric-lamp socket.



R. R. MQILVAIN'EL ELEGTRIC LAMP SOCKET.

APPLIUATION FILED JULY 1a, 1913.

1,090,930, Patented Mar. 24, 19m

WITNESSES ment of screws or other special are RALPH R. MoIL'VAIIi-E, 0F JFILIQNTSBUEG, PENNSYLVANIA.

ElL ECTRIJ-LAIVIP SOCKET.

To all whom it may concern Be it known that l, RALPH R. a citizen of the UnitedStates, residing at Wilkinsbug, in the county of Allegheny and State of Pennsylvania, have invented new and useful Improvements in Electric Lamp Sockets, of which the following is a specification.

My invention relates to holders or sockets for incandescentv electric lamps and itsobject is toprovide an extremely simple device of this character, from which-a lamp cannot be removed without breaking the lamp and which retains all the necessary switch ele ments and terminals without the employ Meir-veins,

Referring to the accompanying drawings,

Figure 1 is a central longitudinal section of 4% of the lamp,

free so that they can act as a brake a socket involving my invention; Fig. 2, a side view of the same with the cap, shell, and lamp removed; Fig. 3, a longitudinal section on the line IlL-lll, Fig. 2; a, a" top view of Fig. 2; and Fig. 5, a side view of one section of the body of the socket.

On. the drawings, 1 and 2 represent the halves of the base-plug, which constitute the body of the holder and are composed of porcelain or other insulating material. lhe said halves meet in aplane which includes the longitudinal center of the lampholder, their lower ends being reduced in cross-section and provided with external screw: threads toreceive one end,.;of the spiral spring or socket member 3 which constitutes the member for securing the halves of the base-plug together and the threaded socket for the threaded base 4 of the incandescent lamp-5. The spring or socket 3, the base and the threaded end, of the base-plug are of such relative dimensions that the spring is slightly opened or put under strain when it is being screwed on the base-plug and when the lamp base is being screwed into the spring, the friction being such as toallow the parts to be readily screwed together, but such as to make the grip of the spring on the base-plug and lamp-plug increase on any attempt to screw of the are left on any reverse movement of the parts screwed into the same. Any reverse movement of either spring to them apart. The convolutions spring are not bound together, but

the plug harder.

Specification of Letters Patent. Application filed July 16, 1913.

Patented Mar. 24, This. serial No. 779,236.

6 is the metal shell provided with the insulating lining 7 which is slid over thebody of the holder from the reduced threaded end toward the larger end. The larger end of the shell and lining have the usual slot 8 for the key 8.

9 is the usual removable cap for the larger end of the shell. The shell extends out to the outer end of the spring or socket 3 and covers the end-of the same as far as practicable so that no tool can be inserted in the shell to partially uncoil the spring devices.

and thereby permit the lamp to be screwed out.

shell and as the lamp cannot be screwed out or the spring socket 3, it is necessar in order to remove the lamp plug or base 4:

from the socket, to break the bulb away frolic. its base. When this has been done, the shell can, after the removal of the cap therefrom, he slid oil from the body of this lamp-holder, so that access can be had to against its free end, the lamp-base to he employing a large number of persons The members 1 and 2 are internally recessed at 10 to receive the contact block 11, carried by the stern of the key 8, the stem having bearings or open recesses in the meeting races of the said halves. Opposite, faces of the contact-block, which is composed of insulating material, are provided with the hat contact strips '12 electrically connected by an intermediate portion thereof orotherwise to the key-stem. The end of the stem opposite the finger piece 13 of the key is provided with the line terminal .14: carrying the binding screw 15. This terminal may be kept in contact with the stem in various ways, but I have shown the stem provided with the annular groove 16. The terr'ninal is providedwith a hole fitting the said groove and preventing the removal of the terminal from the stem.

The center terminal 17 for the lamp consists of a strip of conducting spring metal having one end bent to form the flat head or contact 18 for the usual center lampterminal-;;. The strip has a reverse head or loop 1.9 within the recess in the member 2; where the spring 3, which can be slightly un- 80 As the bulb of the lamp is larger than the tact strip, a center lamp terminal having a bend fitting the lower wall of one of the recesses, a head below the outer bend, and a brush in'one of the recesses and adapted to be engaged by the contact strip when the key is suitably operated.

3. In a holder for a snlating body compo ed cessed members, meanstor securing them together, a rotatable key provided with a stem, and a contact block secured to the stem and provided with a contact strip, a center lamp terminal havin a bend fitting the lower wall of one of t e recesses, a head below the outer bend, and a brush in one of the recesses and adapted to be engaged by the con. tact strip when the key'is suitably operated.

4:. In a holder for an electric lamp, an insulating body composed of Y internally recessed members, means gether, a rotatable key provided with a stem, and a contact block secured to the stem and provided with a contact strip, a line termi nal secured to the stem, and a center lamp terminal held in position bers.

5. In a holder for an electric lamp with a threaded plug, a body comprising a plurality of longitudinal members provided at one end with screw-threads, a coiled spring into which the said which they are held together, and a line ter- .minal held by and between the said spring and the said body. v

6. In a holder'for an electric lamp with a threaded plug, a body provided at one end with screw-threads, a coil spring into which the said body is screwed, and a line terminal held by and between the said spring and the said body.

7. In a holder for an electric lamp, a body member having notched threads, and a 0011 by a space 20 between the loop .and the contact 18 is formed to receive the bottom wall of the said recess, one of the members being recessed,-as at 21 to permit the terminal to extend from the said recess. to the contact or head 18. The recess 21 is preferably of such dimensions as to cause the terminal to be firmly clamped between the members 1 and 2 when screwed into the spring 3. The innor end of the terminal 17 is lectric lamp, an inbent. so as to form a brush or contact finger 22 for engagement with the strips 12. There will, therefore, be two positions of the block 180 apart, at which the line terminals will be electrically connected, and two positions 90 from the other two positions at which the brush 22 will contact with the non-conducting material of the contact block and at which the lineterminals will not be electrically connected, as will be readily understood.

The remaining line terminal marked 23 is provided with the binding screw 24: and has one end clamped between the spring 3 and the body of the socket, as shown in Fig. 2.

The threads on the sections 1 and 2 may have notches as shown on Fig. 5 to cooperate with teeth on the inside of the coil 3, 'the teeth on the coil also serving to hold the lamp plug t with greater force.

I claim-- 1. In a holder for an electric lamp, an insulating body composed of longitudinal members provided with screw-threads on one end, a coiled spring into which the said body is screwed and by which the members are held together, a lamp terminal projecting through the center of the end of the body which is provided with the spring, and rotatable key having a contact block rotatable in recesses in opposing faces of the members and having bearings in the meeting walls or the said members and in sliding contact with the inner end of the said terminal.

2. In a holder for an electric lamp, an insulating body composed of internally-re cessed members, means for securing them tothe threads on the Pa,

lutions in Signed at Pittsburgh, of July, A. D. 1913. v

'RALPH It. MQILVAINE.

body member. this 11th day gether, a rotatable key provided with a stem having bearings in recesses in the opposing Vitnesses:

faces of the said member, and a contact block An on E. DUFF, secured to the stem and provided with a con- F. N. BARBER.

of internally-respring socket member having toothed convo- I for securing them to- I by the said memmembers are screwed and by v 

